Flow Cytometry Core: Project Summary/Abstract Flow cytometry is an essential method in cancer research. It is widely used to identify, track and purify specific cell populations through analysis of cell surface markers and/or fluorescent reporter genes, and also to assess cellular phenotypes, such as cell cycle progression, DNA damage or apoptosis responses. Flow cytometry also supports a broad range of engineering-based approaches, such as quantification of targeting efficiencies for antibody- and copolymer-based therapeutic delivery systems, and high-throughput approaches to develop fluorophore-based protein labeling and imaging technology. The Koch Institute Flow Cytometry Core is a Shared Resource that provides Center Members with training in, and access to, state-of-the-art cell sorting instrumentation, technical expertise and training, and data analyses. In the current period, the capabilities of this Core were further expanded and enhanced. Two new analyzers and two new sorters were acquired, replacing older obsolete instrumentation, and three systems were upgraded with new lasers to expand detection capabilities. Core service usage by Center Member has remained high (93% of Center Members). In addition, using CCSG Developmental Funds, the Core has supported a Research Specialist who has established a suite of single cell-associated technologies, including a collaboration with the Koch Institute Integrated Genomics & Bioinformatics Core to enable high throughput single cell mRNA sequencing. These services are now well-developed services within the Core, and we seek continued, partial funding to support the Research Specialist?s efforts. In the upcoming period, the Flow Cytometry Core will continue to offer a wide range of state-of-the-art services to support the research programs of Center Members and will evaluate emerging capabilities in the context of Center Member needs and interests. The Core intends to evaluate high parameter cell sorting, addition of robotics capabilities for automated sampling, mass cytometry, and multiplexed ion beam imaging. The Core will also expand training opportunities, including hands-on data analysis workshops. This Shared Resource is essential to the success of the Koch Institute mission and provides exceptional value to the CCSG because Koch Institute Members account for 84% of the Core services usage. The requested CCSG budget for Year 49 is increased by 9.2% over the budget in the current period (Year 48), reflecting the request for additional funding to stabilize support for the new single cell analysis capabilities.